The serial number list says that the JD450D started in 1982 just past the serial number shown for the start of the JD450C 1983 production.

The power went up all of 3 HP, so I really don't know why there was an overlap this time. The JD450B units changed over to the wet steering clutches used in the JD450C when the stock of dry-type steering clutch parts was depleted.Īgain, we have an overlap between the JD450C and the JD450D. The JD450B units were produced along with the JD450C until the demand for the non-turbo engine dropped off. However, there are some late JD450B's out there with wet steering clutches. Also, the JD450C changed from dry to wet steering clutches. The main differences between the JD450B and JD450C are that the C went to a 4/219 CID Turbocharged engine from the 4/219 CID normally aspirated engine in the JD450B. We do not know the exact serial number of the last JD450B as a result. There is an overlap in 1975 thru 1976 where JD450B and 450C models were made concurrently. Here are the serial numbers, by year, for the JD450 through JD450G models.